Dimer fatty acid-polyester diol-based polymer, containing isocyanate groups

Abstract

A polyester urethane polymer containing isocyanate groups and being liquid at ambient temperature, obtained by reacting at least one monomeric diisocyanate and dimer fatty acid-based polyester diol having OH-number ranging between 28 and 120 mg KOH / g in NCO / OH ratio of at least 3 / 1, and by subsequently removing large part of monomeric diisocyanate by means of suitable separation process, wherein polymer has NCO content ranging between 1.5 and 6% by wt. and maximum monomeric diisocyanate content of 0.5% by wt. The polymer permits the production of moisture-curing polyurethane compositions for application in ambient temperatures, having improved properties in terms of open time, adhesion, application and weather resistance, with unchanged good properties of storage stability, curing rate, strength, ductility, elasticity and hazardous material classification. Compositions of this type are particularly suitable for use as elastic adhesives in replacement glass for vehicles.

Description

TECHNICAL FIELD[0001]The invention relates to polymers containing isocyanate groups and having a low monomer content, and to the use thereof in moisture-curing polyurethane compositions, especially for use as adhesive for replacement of glass in motor vehicles.STATE OF THE ART[0002]Curable compositions based on polyurethanes are often used as adhesives for elastic bonds, for example in motor vehicle construction. This requires good properties, especially with regard to storage stability, applicability, open time, curing rate, adhesion, strength, elasticity, weathering resistance and hazardous substance classification.[0003]One-component moisture-curing systems are popular, particularly on account of their ease of handling. In general, these systems show good adhesion properties. However, there are applications on specific substrates on which the achievement of good adhesion presents difficulties. One example of this is the bonding of replacement panes in motor vehicles, where the bo...

AI Technical Summary

Benefits of technology

The present invention provides an adhesion promoter for moisture-curing elastic polyurethane adhesives that improves adhesion to difficult substrates without compromising other relevant properties, such as storage stability, applicability, curing rate, blister formation, strength, and elasticity. The adhesion promoter is a polymer based on diisocyanate and dimer fatty acid-based polyester diol, which is liquid at room temperature and has good compatibility with the adhesive. It improves adhesion to residual adhesive bead, the open time, and has no effect on the curing rate, strength, and other relevant properties. Additionally, it improves the weathering resistance of the adhesive and results in a matt surface. The polymer is easy to apply, with good sag resistance and short threading properties.

Problems solved by technology

However, the expression force for the adhesive at room temperature and under cold conditions is increased by the meltable component, and sag resistance is highly shear-dependent, which can lead to problems in production and application.

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